The invention relates to an apparatus for printing, dispensing and applying pressure-sensitive labels adhering to a carrier tape comprising a feed means which draws the carrier tape stepwise round a peel edge which is formed by a roller mounted on a shaft and at which the pressure-sensitive label is detached from the carrier tape and moves into a dispensing position.
Such an apparatus is known from US-PS 3,954,545. In this known apparatus a label can be brought into the dispensing position by first squeezing and then releasing a hand lever. During the squeezing of the lever the label in the apparatus is imprinted, for example with a price, an article number or the like, and on release of the lever the feed means engages the carrier tape and pulls it a length corresponding to the label length round the peel edge. On pulling of the carrier tape round the peel edge the label detaches and moves into the dispensing position beneath the applicator roll. The return of the lever to its starting position is under the action of a spring which must be strong enough to effect transport of the carrier tape. In particular, it must overcome the frictional forces which occur when the carrier tape is pulled round the peel edge. In the known apparatus as peel edge a stationary shaft provided with rollers is employed so that only the friction between the roller inner surfaces and the shaft peripheral surface acts against the pulling of the carrier tape round the peel edge. To ensure that the label detaches cleanly from the carrier tape at the peel edge said edge must be made as sharp as possible. This means that with the specific form of the peel edge outlined above the rollers must have the smallest possible external diameter. Said rollers must be mounted on a correspondingly thin shaft so that there is a danger of the shaft bending under the action of the tensile force exerted on the carrier tape. When this bending occurs the carrier tape is subjected to increased stress at the edges which can even lead to tearing of said carrier tape. The result of such tearing is that the carrier tape must be rethreaded into the apparatus and this represents an undesirable loss of time. The danger of this bending increases of course with increasing width of the labels for which the apparatus is designed.
Although this disadvantage could be compensated by using a shaft of larger diameter for a given roller external diameter the increase in the shaft diameter increases the effect of the frictional moment on the tensile force to be applied for advancing the carrier tape. The effect of the frictional moment on the tensile force is smaller the smaller the shaft diameter for a given roller external diameter.
This disadvantage cannot be obviated by using a shaft of greater diameter because this would impair the clean detachment of the label from the carrier tape.
The problem underlying the invention is to construct an apparatus of the type outlined above in such a manner that independently of the label width rollers of small diameter can be used for obtaining a sharp peel edge and nevertheless the effects of the frictional moment between rollers and shaft are kept small.
This problem is solved according to the invention in that the shaft carrying the rollers is supported between its ends.
Due to the supporting according to the invention of the shaft carrying the rollers said shaft can be made very thin compared with the roller diameter without any danger of said shaft sagging or bending under the influence of the tensile force exerted on the carrier tape. The same small shaft diameter can be used for any label width since if necessary several supports may be provided along the shaft. The carrier tape is stressed in all cases at the peel edge uniformly over its entire width so that there is no danger of the tape tearing. Also, due to the use of a thin shaft the external diameter of the rollers may be kept small so that a peel edge of small radius of curvature is obtained which guarantees good detaching of the pressure-sensitive labels from the carrier tape without the tape feed being impaired by the frictional moment between the rollers and shaft.